Unlike in the Original Campaign, Companions start with fixed XP totals when you find them. Afterwards, they gain XP when you do. Therefore, it is to your advantage to find them as soon as possible so that they benefit from your gaining XP.

Some companions interact with others when you talk to them -- e.g, Gann and Kaelyn. Sometimes, however, this means you will gain Influence with one while losing it with another.

Party Roster
The Party Roster is different than in the Original Campaign. Essentially, you are not using the Party Roster at all. When a Companion is asked to leave temporarily, they are taken OFF your roster rather than held in reserve. A separate copy of them is placed where they wait, and they do NOT gain XP when you do, unlike in the Original Campaign. You can still use the Neverwinter Nights 2 console to change this so that you can have more Companions at the same time and use the Party Roster from the in-game menu or the PartyAdd and PartyRemove commands. There are a couple of weird things that happen, so DO THIS AT YOUR OWN RISK.

First, use rs ga_party_limit(10) to give yourself lots of room in the party. This will not change dialogue checks for party size, so you will still need the Party Roster menu to add companions.

When a Companion is taken out of the party due to dialogue, open the console and use RosterAdd <companion name> to put them back in the roster. The names are pretty straightforward (e.g., RosterAdd Okku) except for Kaelyn the Dove. For the commands, her name is "Dove" rather than Kaelyn.

To put them in / take them out of your current lineup, use the PartyAdd <companion name> and PartyRemove <companion name> commands, respectively.

Note that in doing this, you may encounter HOSTILE copies of your Companions where they normally go when they are out of your party. For example, there will be an hostile Safiya with all the stats and gear she had when you manually added her back to the Roster. When you kill them, they go into "Dying" status and cannot be interacted with. Just leave them alone.

Her Red Wizard feats look impressive, but you still probably won't see much success having enemies fail their saving throws unless you target their weak Saves (e.g., for Rogues, this would be Fortitude and Will; they have Reflex as a strong saving throw).

Safiya has some maxed skills and a few scattered points here and there. For the Craft skills, she doesn't need the maximum in all areas, just modified totals that hit certain thresholds:

Craft Alchemy - 16

Craft Armor - 24 for Umber Hulk Half Plate

Craft Trap - 20 for Deadly Traps

Craft Weapon - 23 for Exotic Weapons

I recommend continuing to maximize Concentration and Spellcraft, then dumping all points into Tumble to catch up as quickly as you can. You cannot re-level to redo her skills her without losing any Red Wizard levels (you can ONLY choose Wizard levels when doing her level advancement), so I recommend against that.

For feats, she is already very focussed and there is really very little reason to want to relevel her. I recommend either Quicken Spell, which isn't normally as useful for a Wizard as it is for a Sorcerer, but nevertheless useful for all spellcasters to quickly put up defenses or suddenly quickly output a lot of damage in a single round -- maybe enough to overwhelm an enemy caster before they can put up defenses (if any). Besides, she is close to Epic levels, and at Spellcraft 30 she can start picking up Automatic Quicken.

As a Red Wizard Transmuter, her spell list is very small. For early levels, I recommend getting Bigby's Interposing Hand and Wail of the Banshee -- The former is a no-save anti-fighter-boss spell and the second is Fortitude Save spell, good against Improved Evasion targets that can completely evade her Reflex save damage spells. Most of the other Bigby's spells require Grapple checks and are generally useless against big boss monsters or high Strength targets.

I recommend against memorizing a lot of spells which require hit rolls, even Touch or Ranged Touch, because at near-Epic levels, enemy AC will generally be high enough that even Touch spells will have a very hard time hitting anything.

Be nice to her, and by the time you talk to the Witches in Mulsantir for the first time she can be Devoted to you with over 70 Influence and secure the Devotion of the Red Wizard history feat.

There is a problem where if you gain too much Influence, the conversation script may not account for it and you can miss the initial conversation to start getting Influence/History feats with her.

The dialogue tree checks at the very start of conversation assuming there is nothing else of higher priority; AND it checks to see if your influence with her is within a certain amount, but does not account for it being greater than that; AND you must be past a certain point in the story, possibly out of the Barrows. So, if you surpass that Influence window last conversation, you won't get your History feat (but Safiya will still get hers normally).

If you miss this initial conversation, you also miss the corresponding feat for your character (2056, "Loyalty of the Red Wizard") and a chance to get another +6 Influence with her during that conversation. To get back on track, you will need to use the Console to manually give yourself feat 2056.

He relies on Wisdom for spells, but Charisma for Spell DC, so it's a tricky choice which way to go with attribute gains. I would concentrate on Wisdom to maximize it as his levelling has focussed on that. It also helps with his ability with ranged weapons since he has Zen Archery.

Diplomacy (and initially, Spellcraft on the wards in the Mulsantir Prison) can get you Influence with Gann. He in influenced by sparring with wit or playing on his vanity/hubris. You can get over 60 Influence with him just by talking to him during and after recruiting him from the Mulsantir Prison -- more than enough to get the Dreamer's Eye history feat. You won't get more than this until after he confronts his mother.

Since he can use a shield, you may consider putting his bow on backup and using thrown weapons or slings (you can buy the hideously expensive Dragon Pebbles in Mulsantir). You might also consider aiming for Tower Shield and Improved Combat Expertise to make him a defensive character and front-line spellcaster.

The Attack Penalty from Tower Shields does not apply to ranged combat, and is of course of no consequence if you are casting a spell that does not require a hit roll to begin with.

You cannot use both Combat Casting and Combat Expertise, so you will have to choose when to use them. There are pros and cons to both -- With Combat Casting you don't provoke an Attack of Opportunity, but you may still be attacked normally so it is not necessarily superior when swarmed. With Combat Expertise, you will provoke Attacks of Opportunity from everyone who can make one, but at +3 or +6 AC, you can make it hard to be hit at all).

Because he is a spontaneous caster (like a Sorcerer) who does not need to choose which spells to know each day, you may want to tweak him into a battle-caster.

Unlike Qara in the Original Campaign, since Gann starts at a high enough level to have level 8 spells, we can skip the spell level +1 adjustment feats and go straight to Empower Spell first.

If you are not averse to cheating, use the console to remove Dodge, Weapon Focus (Short Bow) and Improved Critical (Short Bow), and change them to supporting feats, such as Tower Shield and Improved Combat Expertise.

You can raise her Influence to 53 when you first meet and talk, and Gann's by +6. You can favour Gann by another +6 if you disagree with Kaelyn about the wall, but it will cost you a lot of Influence with her, and you may already have lots with Gann at that time. At 50+ Influence, you can get the Blessing of the Menagerie. By Influence 30, when her greeting to you changes, she has already gotten a corresponding blessing on herself.

If your deity is Ilmater, you can gain one-time Influence with her.

Kaelyn has an enormous Wisdom score so she theoretically makes a good caster.

Spell DC is not based on character level, but spell level and spellcasting attribute bonus (in this case, Wisdom).

Penetrating Spell Resistance, however, IS based on character level, and since she has an ECL +4 racial adjustment, this means she more or less has a -4 penalty to penetrate SR compared to everyone else. Definitely aim for Spell Penetration feats if you are going to make her a battle caster.

Her ECL +4 racial adjustment (and low Strength) means her combat ability, already less than that of a fighter because of the +3 per 4 level Cleric BAB progression, suffers even more. Like Gann, I recommend making her a front-line caster and put her combat on backup. She has more of an advantage here because she can wear heavy armor.

If you are bent on having her fight, then make sure she has Zen Archery to take advantage of her enormous Wisdom score. Her wings give her +20% movement, so keep her unencumbered and micromanage her flying around as a skirmisher or leading the enemy about so other characters can score free Attacks of Opportunity as the pursuers run by.

She starts with no metamagic feats, which isn't a huge drawback considering her high Wisdom gives her a lot of spells. But with not many feats left to choose, you may want to consider aiming for Persistent Spell and splitting her spell list into daily party buffing and the rest into combat spells and healing.

Another option is to make her a crafter, giving her access to enchantments that require divine spells. This isn't as critical in Mask of the Betrayer because in the Original Campaign, many enemies were evil-aligned, making Holy Weapons (which require Cure Critical Wounds to enchant) sovereign. In Mask of the Betrayer, your enemies are not always conveniently evil and there are wider options for enchantments and enchanting. Also, your main character will end up doing the higher-level enchanting on their own with the Mold Spirit feat.

In order to get One of Many, you need a Spirit Husk, which you get after devouring the spirit of Okku when you fight him at the end of Act I. You can have both One of Many and Okku in your party by using the Console command giveitem nx1_b_spirithusk to get that item. Devouring Okku also gives you Okku's Essence (nx_1_cft_ess_okku).

To get the Warlock persona, you need to have One of Many (or yourself, if you learnt the feat from U'juk) use Devour Soul on either The Sleeper or Gulk'aush. At Epic levels, the Warlock persona can cast Vampiric Feast.

One of Many is hard to Influence without alienating everyone else. To tweak its Influence, use rs ga_global_int("00_nInfluenceoneofmany","30") to, for example, set Influence to 30. Influence cannot be over 100 for any character.